W 2K will not boot and won't recog graph card

Hello, I have problems with bootup, it will not recognise graphics card at all. I have changed to a few of the old cards I had laying around but, nothing. BTW, the splash screen and post do not even come up, just blank screen. I have tried removing everything but graphics card to no avail. I also can't remember all the things I have on this system, not to mention all the software. Someone please help me get it going again!